The invention relates generally to an integrated thin-film device with a solar cell, an integrated battery and an electronic controller. The invention relates further to a method for manufacturing a related monolithically integrated device. Solar cells are photovoltaic devices which convert sunlight into electricity.
Solar cells are either made of crystalline silicon wafers or are based on thin-film silicon technologies. Alternatively, solar cells may be based on amorphous silicon. Other alternatives may be based on CIGS (Copper-Indium-Gallium-(Di-(Selenide)), CdTe (Cadmium-Telluride) or CZTS (Copper-Zinc-Tin-Sulfide). Solar cells are used in a wide range of applications. They may, e.g., be used to deliver power into a public power grid, recharge batteries in remote locations, recharge mobile devices like mobile telephones, or may function as a sole energy source for pocket calculators. One key design parameter for solar cells is the production price in relation to the efficiency of the conversion process from light energy to electrical energy.
One problem of solar cells is their direct dependence on incoming light. In order to charge batteries efficiently using solar cells, additional electronic components may be required. The electronic components or circuits may be used to transform and reshape the output voltage of solar cells or solar cell modules comprising several solar cells. Individual solar cells have non-linear output efficiency due to the relationship between solar radiation, temperature, and total resistance.
To maximize power output of a solar cell module, solar cell arrays may use one or many different maximum power point tracking (MPPT) techniques. Such devices are typically integrated into a power converter system which provides voltage or current conversion, filtering, and regulation for driving various loads in power grids and batteries. In order to keep price points for production low, solar cells may be integrated with these required additional electronic components.
On the other side, there have been approaches to integrate a solar cell with a prefabricated battery. Such an approach has been described in US 2009/0288700 A1. The document relates to an integrated device comprising at least one inorganic photovoltaic cell, a substrate supporting the inorganic photovoltaic cell, a prefabricated battery coupled to the at least one inorganic photovoltaic cell, and an encapsulation for sealing the integrated device.
Additionally, US 2012/0043814 A1 discloses an integrated photovoltaic electronic cell and battery device. The integrated device includes a photovoltaic cell, a battery, and interconnects providing a three-dimensional integration of the photovoltaic cells and the battery into an integrated device for capturing and storing solar energy.
However, there remains a need to produce high quality thin-film solar modules at low prices ensuring a long life of integrated batteries and easy connectivity to a power grid or other power consumers.